Oil field pump

ABSTRACT

An oil field pump is installed within a pipe that connects to an oil field, and feeds accumulated extraction oil in a predetermined direction, the oil field pump including a rotor formed with an internal flow path for the extraction oil, a stator mounted on the outer circumference of the rotor, a thrust bearing that supports the axial weight of the rotor and the stator, and a supply pipe that supplies a portion of the extraction oil from the center side in the rotational direction of the flow path to the thrust bearing.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and incorporates by referencethe entire contents of Japanese Patent Application No. 2019-102335 filedin Japan on May 31, 2019.

FIELD

The present invention relates to an oil field pump installed in oilfields.

BACKGROUND

Oil fields extract oil by way of oil field equipment including pipesconnecting to positions where oil can be extracted and pumps installedwithin the pipes to feed the oil within the pipes. The pumps areinstalled within the fluid in the pipes and feed the oil within thepipes to the oil extraction port. The pumps feed oil extracted from oilfields and the fluid therefore sometimes contains foreign matter. Theforeign matter mixes in between rotating parts and stationary parts andcauses breakdown if the foreign matter accumulates as deposits.

The technology for example in Patent literature 1 discloses a rotaryshaft mechanism including a flow path extending on the circumference ofa rotary shaft in sliding contact with the inner circumferential side ofa cylindrical-shaped bearing and with at least one end and the other endformed with an opening on the outer circumferential surface of therotary shaft.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Application Laid-open No.2016-130491 A

SUMMARY Technical Problem

Here, the oil field pump includes a pump body containing an impeller tocompress and feed extraction oil, and a motor connecting to the pumpbody that serves as a drive source. The oil field pump further includesa bearing mechanism. When lubricating oil is supplied to the rotaryshaft mechanism, installing supply lines for lubricating oil across theentire area or performing periodic maintenance is needed. In contrast,when lubricating the bearing mechanism with extraction oil, foreignmatter might possibly contaminate the bearing mechanism of the oil fieldpump. The device according to Patent literature 1 can reduce the effectof the foreign matter but requires improvements.

To resolve the aforementioned problems with the related art, the presentinvention has the objective of providing an oil field pump capable ofreducing the need for frequent maintenance.

Solution to Problem

To achieve the above object, an oil field pump installed within a pipethat connects to an oil field, the oil filed pump being configured tofeed accumulated extraction oil in a predetermined direction isdisclosed. The oil field pump includes a rotor formed with a flow pathfor the extraction oil therein, a stator mounted on an outercircumference of the rotor, a thrust bearing that supports an axialweight of the rotor and the stator, and a supply pipe that supplies aportion of extraction oil from a center side in a rotational directionof the flow path to the thrust bearing.

It is preferable that the thrust bearing includes a protrusion partfixed to the outer circumference of the rotor and rotating as one piecewith the rotor, and a facing part fixed to the stator and facingopposite a surface in an axial direction of the protrusion part, and theextraction oil is filled between the protrusion part and the facingpart.

It is preferable that a portion of the supply pipe protrudes into theflow path.

It is preferable that an end of the supply pipe on the flow path side isinstalled along the flow direction of the extraction oil on the flowpath.

It is preferable that the supply pipe is open on an end surface on aninner side of the flow path in a radial direction.

It is preferable that the oil field pump further includes a dischargepipe that discharges the extraction oil supplied to the thrust bearingto further downstream than a connector of the supply pipe of the flowpath.

Advantageous Effects of Invention

The present invention is capable of reducing the need for frequentmaintenance.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an overall structural view of an oil extraction deviceincluding an oil field pump of the embodiment of the present invention.

FIG. 2 is a fragmentary cross sectional view of the oil field pumpillustrated in FIG. 1.

FIG. 3 is a cross-sectional view illustrating one example of themechanism that supplies extraction oil to a thrust bearing.

FIG. 4 is a cross-sectional view illustrating another example of themechanism that supplies the extraction oil to the thrust bearing.

FIG. 5 is a cross-sectional view taken along line A-A in FIG. 4.

FIG. 6 is an overall structural view illustrating another example of thethrust bearing.

FIG. 7 is an overall structural view illustrating another example of thethrust bearing.

DESCRIPTION OF EMBODIMENTS

The embodiment of the present invention is described next whilereferring to the drawings. The present invention is not limited by thisembodiment. The structural elements in the following embodiment can beeasily substituted by one skilled in the art or may include essentiallythe same item.

FIG. 1 is an overall structural view of an oil extraction deviceincluding an oil field pump of the embodiment of the present invention.An oil extraction device 10 is installed on an installation surface 2.The installation surface 2 is a structure installed at an oil field 4.When the oil field 4 is on the ocean floor or in other words, when theoil field 4 is an offshore oil field, the installation surface 2 is astructure at sea level. When the oil field 4 is below ground, theinstallation surface 2 is a structure at ground level. The oil field 4is an area to accumulate the oil for extraction.

As illustrated in FIG. 1, the oil extraction device 10 includes a pump(oil field pump) 12, a pipe 14, a ground facility 16, and a guide pipe18. The pump 12 is equipment that feeds the extraction oil Q accumulatedin the oil field 4. The extraction oil Q might contain solid matter suchas ores in addition to the crude oil. The pipe 14 is a flow path for theflow of extraction oil therein. One end of the pipe 14 is installed inthe oil field 4 and the other end is connected to the ground facility16. The pump 12 is installed at a section on the oil field 4 side in thepipe 14. The ground facility 16 includes a device to wind up a wire 20such as a coil turbine or a wire winder mechanism described below. Theguide pipe 18 guides the extraction oil.

The pump 12 is described next while referring to FIG. 2 and FIG. 3 inaddition to FIG. 1. FIG. 2 is fragmentary cross sectional view of theoil field pump illustrated in FIG. 1. FIG. 3 is a cross-sectional viewillustrating one example of the mechanism that supplies the extractionoil to the thrust bearing. The pump 12 includes a wire 20, a pump body22, a coupler 24, a motor 26, a stationary pipe 28, an electric cable29, a thrust bearing 50, and a supply pipe 62.

The pump body 22, the coupler 24, and the motor 26 (rotor 30 describedbelow) are integrally connected in the pump 12. The upper end of thepump body 22 connects to the wire 20. The wire 20 can be wound up andfed out by the above described ground facility 16. The stationary pipe28 fixes a stator 32 that is a portion of the motor 26. The extractionoil Q can flow within the interior of the stationary pipe 28. Theelectric cable 29 connects between the ground facility 16 and the stator32 and supplies electrical power to the stator 32.

In the pump 12 of the present embodiment, the pump body 22, the coupler24, and motor 26, are detachable from the electric cable 29. In otherwords, winding the wire 20 separates the pump body 22, the coupler 24,and the rotor 30 of the motor 26 as an integrated piece from the stator32 and raises them upward within the stationary pipe 28. This structurecan easily insert and pull up the pump body 22, the coupler 24, and therotor 30 as an integrated piece so that installing a large scale rig orsimilar equipment at the installation surface 2 is not necessary.

The motor 26 includes the rotor (rotating part) 30 and the stator(stationary part) 32. The rotor 30 is a cylindrical shape. A flow path34 for the flow of extraction oil Q therein is formed in the rotor 30.The flow path 34 for the flow of extraction oil Q connects to a flowpath of the connecting part 24. In the connecting part 24, flow paths56, 58 and a branch part 60 are formed as passages for extraction oil Q.The flow path 56 connects to the flow path 34 and the branch part 60.The branch part 60 supplies the extraction oil Q that flows within therotor 30 to a space between the rotor 20 and the stator 32. The flowpath 58 is installed on the upper side perpendicular to the branch part60, and the internal circumferential surface forms the rotor 30 and theexternal circumferential surface forms the stator 32. The flow path 58connects to the flow path of the pump 22.

The rotor 30 can rotate centering on the center axis CL. The rotor 30includes a permanent magnet 40. The permanent magnet 40 is mounted asone piece with the rotor 30 on the outer circumference of the rotor 30.The stator 32 includes an electromagnet 42. The electromagnet 42generates a magnetic field from the electrical power supplied from theelectric cable 29. The interaction between the magnetic field generatedfrom the electromagnet 40 and the magnetic field generated from thepermanent magnet 42 allows rotation of the rotor 30 centering on thecenter axis CL. An impeller of the pump 22 is mounted on the upper sideperpendicular to the rotor 30. Rotation of the rotor 30 rotates theimpeller that forms one piece with the rotor 30. The rotation of theimpeller compresses and feeds the extraction oil Q on the periphery tothe interior of the rotor 30. In other words, the rotor 30 rotates asone piece by the attachment with the rotor (rotating part) of the pump12. The stator 32 is attached to the stator (stationary part) of thepump 12.

In the coupler 24, the upper end along the central axis of the rotor 30is inserted into the lower end of the stationary pipe 28. The flow path56 is connected to the branch part 60 within the stationary pipe 28. Thebranch part 60 feeds the extraction oil Q flowing upwardsperpendicularly within the flow path 34 radially to the outer side R.

The thrust bearing 50 includes a protrusion part 70, a retainer part 72including a facing part 72 a, and a retainer part 74 including a facingpart 74 a. The protrusion part 70 is fixed to the outer circumference 30a of the rotor 30 and rotates as one piece with the rotor 30. Theprotrusion part 70 is for example, a disk shape and includes a firstsurface 70 a and a second surface 70 b mounted on the front and rearalong the axial direction of the center axis CL. In the presentembodiment, for example, the first surface 70 a is a surface on thelower side in a perpendicular direction, and the second surface 70 b isa surface on the upper side in a perpendicular direction. The facingpart 72 a is the surface opposite the first surface 70 a of theprotrusion part 70. The facing part 74 a is a surface opposite thesecond surface 70 b of the protrusion part 70. The protrusion part 70includes a cylindrical-shaped side surface 70 c centering on the centeraxis CL. The side surface 70 c is a surface opposite an innercircumferential surface 28 a of the stationary pipe 28. On the retainerparts 72, 74, the bearing pads 76 are mounted on the surface facing theprotrusion part 70. The facing part 72 a and the facing part 74 a arethe front surfaces of the bearing pads 76.

Gaps G filled with lubricating oil are respectively formed between thefirst surface 70 a and the facing part 72 a, between the second surface70 b and the facing part 74 b, and the side surface 70 c and the innercircumferential surface 28 a. By filling the extraction oil into thegaps G, the thrust bearing 50 can smoothly rotate the rotor 30, and cansupport the axial weight on the center axis CL between the rotor 30 andthe stator 32. The extraction oil Q extracted from the oil field 4 isutilized as the lubricating oil. The structure for supplying theextraction oil Q to the gap G is described below.

As illustrated from FIG. 1 through FIG. 3, the supply pipe 62 isinstalled within the flow path 56 and the rotor 30. The supply pipe 62supplies a portion of the extraction oil Q from the center side in therotational direction of the flow path 56 to the thrust bearing 50. Thesupply pipe 62 includes a protrusion pipe 62 a protruding into the flowpath 56, and a rotor internal pipe 62 b formed in the interior of therotor 30. The protrusion pipe 62 a protrudes towards the inner side inthe radial direction R from an area bordering the branch part 60 in therotor 30 and the top end of the protrusion pipe 62 a curves downward.The protrusion pipe 62 a includes an oil extraction port 62 c on thelower end. The oil extraction port 62 c is installed on the center sideof the radial direction R of the flow path 56. The rotation of the rotor30 causes a centrifugal force to act on the extraction oil Q flowingwithin the flow path 56. This centrifugal force causes the solid mattersuch as ores contained within the extraction oil Q to centrifugallyseparate to the outer side in the radial direction R in the flow path56. The extraction oil Q flowing on the outer side in the radialdirection R of the flow path 56 therefore has a large solid mattercontent. The extraction oil Q flowing on the center side in the radialdirection R of the flow path 56 has little solid matter content. A solidmatter content distribution in this way forms in the radial direction R,between the outer side and the center side in the flow path 56. In thepresent embodiment, the extraction oil Q can be efficiently collected ina state with little solid matter by installing the oil extraction port62 c on the center side in the radial direction R of the flow path 56.

The oil extraction port 62 c faces downward in the perpendiculardirection. The protrusion pipe 62 a extends upward from the oilextraction port 62 c. The end of the supply pipe 62 on the flow path 56side is installed along the flow direction of the extraction oil Q inthe flow path 56. The extraction oil Q flowing from the lower side tothe upper side in the perpendicular direction within the flow path 56can therefore be efficiently collected.

The rotor internal pipe 62 b extends along the axial direction of thecenter axis CL in the interior of the rotor 30. One end of the rotorinternal pipe 62 b connects to the protrusion pipe 62 a. The other endof the rotor internal pipe 62 b bends to the outer side in the radialdirection R at a position height corresponding to the thrust bearing 50,and connects to the supply port 62 d formed on the outer circumferentialsurface 30 a of the rotor 30. The supply port 62 d is mounted near thegap G of the thrust bearing 50. The extraction oil Q collected from theoil extraction port 62 c flows out from the supply port 62 d by way ofthe protrusion pipe 62 a and the rotor internal pipe 62 b. A portion ofthe extraction oil Q flowing out from the supply pipe 62 d flows upwardsand a portion of the extraction oil Q is supplied to the gap G.

FIG. 4 is a cross-sectional view illustrating another example of themechanism that supplies the extraction oil Q to the thrust bearing. FIG.5 is a cross-sectional view taken along line A-A in FIG. 4. Asillustrated in FIG. 4, the supply pipe 66 may be configured to collectthe extraction oil Q flowing in the flow path 58 on the downstream side(upper side in FIG. 4) of the branch part 60 and supply the extractionoil Q to the thrust bearing 50.

As illustrated in FIG. 4, the supply pipe 66 is formed within the rotor30. The supply pipe 66 includes an oil extraction port 68 a open on theend surface on the inner radial side R of the flow path 58 among theouter circumferential surface 30 a of the rotor 30, a supply port 68 bformed at a position corresponding to the thrust bearing 50 among theouter circumferential surface 30 a of the rotor 30, and a rotor internalpipe 68 c that connects with the oil extraction port 68 a and the supplyport 68 b.

The oil extraction port 68 a faces the inner circumferential side in theradial direction R of the flow path 58. Rotation of the rotor 30 causesthe already described centrifugal force to also act on the extractionoil Q flowing within the flow path 58. This centrifugal force causes thesolid matter such as ores contained within the extraction oil Q tocentrifugally separate in the outer circumferential side in the radialdirection R of the flow path 58. The extraction oil Q flowing on theouter circumferential side in the radial direction R of the flow path 58therefore has a large solid matter content. The extraction oil Q flowingon the inner circumferential side in the radial direction R of the flowpath 58 also has little solid matter content. A solid matter contentdistribution in this way forms between the outer circumferential sideand the inner circumferential side in the radial direction R in the flowpath 58. In the present embodiment, the extraction oil Q can beefficiently collected in a state with little solid matter by installingthe oil extraction port 68 a facing the inner circumferential side inthe radial direction R of the flow path 58.

As illustrated in FIG. 5, a plurality of rotor internal pipes 68 c areinstalled around the axial direction of the center axis CL so as toprevent interfering with the branch part 60. Installing the rotorinternal pipes 68 c at a plurality of locations allows a uniform supplyof the extraction oil Q in the rotational direction of the thrustbearing 50.

As illustrated in FIG. 5, a plurality of the branch parts 60 areinstalled along the axial direction of the center axis CL. Each of thebranch parts 60 in the sectional view is formed in a linear shapeintersecting in the rotational direction of the rotor 30. Due tocentrifugal separation in the flow path 56 within the rotor 30, thesolid matter content in the extraction oil Q flowing on the outer sidein the radial direction R becomes large. The rotation of the rotor 30forms a flow along the direction of rotation of the rotor 30 in the flowpath 56. In other words, a large amount of solid matter flows along therotational direction of the rotor 30 on the outer side in the radialdirection R. In the example in FIG. 5, a branch part 60 is formed so asto intersect the rotational direction of the rotor 30. Therefore, whenthe rotor 30 rotates, the inflow of solid matter into the branch part 60is suppressed. The structure illustrated in FIG. 3 as described above,may be formed so that the branch part 60 intersects the rotationaldirection of the rotor 30, the same as the structure illustrated in FIG.5.

As illustrated in the structure in FIG. 5, a discharge pipe 92 isinstalled within the stationary pipe 28. The discharge pipe 92 includesan inflow port 92 a, a discharge port 92 b, and a stationary pipe innerpipe 92 c. The inflow port 92 a is opened at a portion of an areacorresponding to the gap G on the inner circumferential surface 28 a ofthe stationary pipe 28. The discharge port 92 b is open furtherdownstream (upper side in FIG. 5) than the oil extraction port 68 a ofthe supply pipe 66 among the inner circumferential surface 28 a of thestationary pipe 28.

In this structure, among the extraction oil Q flowing from the branchpart 60 in the flow path 58, a portion of the extraction oil Q flowingon the inner circumferential side in the radial direction R of the flowpath 58, flows into the oil extraction port 68 a. The extraction oil Qflowing into the oil extraction port 68 a, flows through the connector68 c, and flows out from the supply port 68 b. A portion of theextraction oil Q flowing out from a supply port 68 d flows upward and aportion of the extraction oil Q flows to the gap G. The extraction oil Qsupplied to the gap G is discharged via the discharge pipe 92 to furtherdownstream than the oil extraction port 68 a of supply pipe 66 among theflow path 58.

FIG. 6 is an overall structural view illustrating another example of thethrust bearing. As illustrated in FIG. 6, the thrust bearing 50 a may beformed in multiple steps along the axial direction of the center axisCL. This structure disperses the load on the thrust bearing 50 a in theaxial direction along the center axis CL. Therefore, the surfacepressure acting on each single thrust bearing 50 a is reduced and thegap G can be enlarged. In structures utilizing extraction oil Qcontaining solid matter as lubricating oil, the bite-in of solid matteramong the first surface 70 a, the second surface 70 b, and the facingparts 72 a, 74 a of the protrusion part 70 is reduced and a long lifecan be achieved.

FIG. 7 is an overall structural view illustrating another example of thethrust bearing. As illustrated in FIG. 7, when the thrust bearing 50 bis formed in multi-stages along the axial direction of the center axisCL, a spring part 78 may be installed between the protrusion part 70 andat least either of the retainer parts 72, 74. The surface pressureacting on each single thrust bearing 50 a can in this way be a uniformsurface pressure. The bearing pads 76 may also be installed on theprotrusion part 70.

As illustrated in FIG. 6 and FIG. 7, when multi-stage thrust bearingsare installed, the supply pipes 62, 66 may be installed at eachprotrusion part 70 gap, or may be installed so that the extraction oil Qis supplied to the gap of the next protrusion part after passing the gapof one protrusion part.

The pump 12 of the present embodiment in this way serves as an oil fieldpump installed within a pipe 14 connecting to the oil field 4 that feedsthe accumulated extraction oil Q in a predetermined direction, and thatincludes the rotor 30 formed with a flow path for the extraction oil Qtherein, the stator 32 installed on the outer circumference of the rotor30, the thrust bearing 50 that supports the axial weights on the centeraxis CL of the rotor 30 and the stator 32, and the supply pipes 62, 66that supply a portion of the extraction oil Q from the center side inthe rotational direction of the flow paths 56, 58 to the thrust bearing50.

The above described structure forms an area with a large content ofsolid matter and an area with a small content of solid matter by way ofcentrifugal separation that is exerted on the extraction oil Q flowingin the flow path, and it is therefore possible to collect the extractionoil Q having a small solid material content. The solid matter contentcontained within the extraction oil serving as lubricant oil that issupplied to the thrust bearing 50 can therefore be reduced. The need forfrequent maintenance can in this way be reduced.

In the pump 12 of the present embodiment, the thrust bearing 50 includesa protrusion part 70 that is fixed to the outer circumference of therotor 30 and rotates as one piece with the rotor 30, and the facingparts 72 a, 74 a fixed to the stator 32 and facing opposite the axialdirection of the protrusion part, and the extraction oil Q is filledinto the gap G between the protrusion part 70 and the facing parts 72 a,74 a. Therefore, the extraction oil Q having a small solid materialcontent can be securely supplied to the thrust bearing 50.

In the pump 12 of the present embodiment, a portion of the supply pipe62 protrudes into the flow path 56. The extraction oil Q flowing in thearea near the center side from the radial direction of the flow path 56can in this way be collected.

In the pump 12 of the present embodiment, the end of the supply pipe 62on the flow path 56 side is installed along the flow direction of theextraction oil Q in the flow path 56. The extraction oil Q flowing fromthe lower side to the upper side in the perpendicular direction withinthe flow path 56 can therefore be efficiently collected.

In the pump 12 of the present embodiment, the supply pipe 66 is open onthe end surface on the radial direction side of the flow path 58. Theextraction oil Q having small solid matter content can in this way becollected.

The pump 12 of the present embodiment includes a discharge pipe 92 thatdischarges the extraction oil Q supplied to the thrust bearing 50 tofurther downstream side than the oil extraction port 68 a of the supplypipe 66 of the flow path 58. A flow can in this way be formed for theextraction oil Q supplied to the thrust bearing 50 and therefore newextraction oil Q can be supplied to the thrust bearing 50.

The technical scope of the present invention is not limited to the aboveembodiment and changes in a range not departing from the spirit andscope of the present invention may be added.

REFERENCE SIGNS LIST

2 Installation surface

4 Oil field

10 Oil extraction device

12 Pump

14 Pipe

16 Ground facility

18 Guide pipe

20 Wire

22 Pump body

24 Coupler

26 Motor

28 Stationary pipe

28 a Inner circumferential surface

29 Electric cable

30 Rotor

30 a Outer circumference

32 Stator

34, 56, 58 Flow path

40 Electromagnet

42 Permanent magnet

50, 50 a, 50 b Thrust bearing

60 Branch part

62, 66 Supply pipe

62 a Protrusion pipe

62 b, 68 c Rotor internal pipe

62 c, 68 a Oil extraction port

62 d, 68 b, 68 d Supply port

68 c Connector

70 Protrusion part

70 a First surface

70 b Second surface

70 c Side surface

72, 74 Retainer part

72 a, 74 a Facing part

78 Spring part

92 Discharge pipe

92 a Inflow port

92 b Discharge port

92 c Stationary pipe inner pipe

CL Center axis

G Gap

Q Extraction oil

R Radial direction

1. An oil field pump installed within a pipe that connects to an oilfield, the oil filed pump being configured to feed accumulatedextraction oil in a predetermined direction, the oil field pumpcomprising: a rotor formed with a flow path for the extraction oiltherein; a stator mounted on an outer circumference of the rotor; athrust bearing that supports an axial weight of the rotor and thestator; and a supply pipe that supplies a portion of extraction oil froma center side in a rotational direction of the flow path to the thrustbearing.
 2. The oil field pump according to claim 1, wherein the thrustbearing includes a protrusion part fixed to the outer circumference ofthe rotor and rotating as one piece with the rotor, and a facing partfixed to the stator and facing opposite a surface in an axial directionof the protrusion part, and the extraction oil is filled between theprotrusion part and the facing part.
 3. The oil field pump according toclaim 1, wherein a portion of the supply pipe protrudes into the flowpath.
 4. The oil field pump according to claim 3, wherein an end of thesupply pipe on the flow path side is installed along the flow directionof the extraction oil on the flow path.
 5. The oil field pump accordingto claim 1, wherein the supply pipe is open on an end surface on aninner side of the flow path in a radial direction.
 6. The oil field pumpaccording to claim 5, further comprising a discharge pipe thatdischarges the extraction oil supplied to the thrust bearing to furtherdownstream than a connector of the supply pipe of the flow path.